The degree of polarity of a molecule is expressed in terms of a “dipole moment.” Molecules, such as water, that exhibit a separation of charge within the molecule, have non-zero dipole moments. If the separated charges are equal in magnitude but opposite in sign, the magnitude of the dipole moment is equal to the product of the value of one of the separated charges and the distance of separation between the charges. The dipole moment is a vector that points from the negatively charged side of the molecule to the positively charged side of the molecule. The dipole moment depends on three factors, namely, (1) polarity of the molecule, (2) the magnitude of the separated charge, and (3) the geometry of the molecule. It is known that different molecules will have different dipole moments.
The present invention uses differences in the dipole moments of different molecules as a means for detecting the presence of contaminants in a fluid.